1. Field of the Invention
The present invention is broadly concerned with an improved, high-capacity patty forming apparatus adapted for use in the commercial production of meat patties formed of, e.g., chicken, beef or pork. More particularly, it is concerned with such an apparatus which in preferred forms includes a reciprocating slide plate equipped with a removeable, multiple piston and cavity head adapted to receive and form patties, and with piston-adjusting mechanism permitting both individual and ganged adjustment of patty thickness without the necessity of piston removal; moreover, the preferred apparatus includes pistons having porous meat-engaging faces together with structure for delivering bursts of pressurized air through the piston faces in order to positively disengage the formed patties from the respective cavities.
2. Description of the Prior Art
Large food processors supplying meat patties to restaurants and fast food chains make use of industrial sized patty forming equipment. Obviously, such equipment is essential in order to economically produce the huge quantities of meat patties needed to meet customer demand.
One type of known patty forming device is described in U.S. Pat. No. Re. 30,096. This machine, known as a "Formax" patty former, is characterized by an apertured slide plate which is shiftable between a retracted position wherein meat is received within the patty forming apertures thereof, and an extended position wherein the formed patties are ejected from the slide plate. For this purpose, the machine is equipped with a stationary ejector device located at the patty discharge position and provided with multiple, up and down reciprocal patty knock-outs.
While slide plate devices of this type have achieved a measure of use in the industry, a number of problems remain. First, the output capacity of these machines is normally limited to a maximum of no more than 4,000 pounds of meat per hour, or 80 cycles of the patty forming mechanism per minute, whichever is achieved first. This capacity is significantly lower than the requirements of many present-day patty forming operations.
In addition, slide plate formers of the type disclosed in the referenced patent require that the slide plate be changed in order to alter the thickness or size of the patties being formed. Such a changeover operation entails considerable effort and down time, and is therefore costly.
Finally, many users of Formax machines have experienced considerable problems and expense by virtue of the need for rather frequent parts replacement. This problem is believed to be partially due to the use of fixed position patty knock-outs as described above, which can become misaligned with the slide plate apertures and, during high speed operations, induce extreme machine vibrations.
Another type of prior patty forming apparatus is described in U.S. Pat. No. 4,193,167. This type of machine employs a rotatable turret plate equipped with a series of spaced patty forming cavities, each of the latter including a shiftable piston therein. Up and down movement of the pistons is controlled via an overhead cam arrangement, so that, as the turret rotates, the meat is first delivered to individual cavities and thereafter deposited in patty form on a belt or the like.
Turret machines suffer from many of the problems of prior slide plate devices, particularly low output (typically, such machines can produce patties only one at a time as the turret rotates). Furthermore, such machines are particularly difficult to adjust so that all patties produced by the respective cavity/piston assemblies are of uniform size and weight. That is to say, with such turret machines, it is virtually impossible to individually adjust the respective pistons so as to give precisely even patty weights from all cavities.
In order to insure patty discharge from the turret cavities, use is made of a continuous moving cut-off band located adjacent the patty discharge position and designed to strip the patties from the individual pistons. Expedients such as these have proved to be troublesome in that meat tends to "hang up" on the stripper and/or piston. This leads to deformed patties, improper patty weights, and generally unsanitary conditions.